Your arguments are without merit, and are oblivious to the facts.
An attempt to undermine the President and his administration by leaking the information from classified meetings would meet the thresh hold of treason.
Incorrect. There is no clause in the legal definition of treason that includes the president or his administration. I don't know if you read legal definition in the link I provided, but here it is:
Whoever, owing allegiance to the United States, levies war against them or adheres to their enemies, giving them aid and comfort within the United States or elsewhere, is guilty of treason and shall suffer death, or shall be imprisoned not less than five years and fined under this title but not less than $10,000; and shall be incapable of holding any office under the United States.
If the person or persons doing the leaking is specifically intending to harm the
country then it would be
closer to treason, but even then the threshold for treason is very, very high. Otherwise, we'd see anybody who leaked classified information charged with treason. Not even Aldrich Ames, Robert Hanssen, or Jonathan Pollard were charged with treason and they were all selling highly classified information to various foreign governments. They were all charged under the Espionage Act.
Your definition of "an attempt to undermine the president and his administration" is nowhere to be found in the legal standards.
The question then becomes, do you believe releasing classified information in an unauthorized manner as a whole should be considered worthy of treason, or only when it's because they don't like Trump?
Plus, there is detailed training called "Cooperating with the Inspector General" which details what the IG can do and what an employee must do in the event of an IG investigation. Trust me, if this guy (IG) or his subordinates decides to sequester (and this is a proper use of the word) an individual in a closed conference room in an attempt to get down to the facts, and that person refuses, it's a removal of all credentials and an escort off the premises by armed security. And that's only the beginning.
I'm not disputing the authority of the IG to conduct an investigation. I'm not disputing that an IG can pull someone into a room to interview them or otherwise determine what's going on. The implication from your original post was that they should be detained, since to sequester usually means to isolate or hide away for a period of time. If you meant simply to interview, then I agree. If you meant to hold for any period longer than an interview, then that would be incorrect. If either one of those is not what you meant, please clarify so we're on the same page.